JPS6186134A - Wire electric spark machine - Google Patents

Abstract

PURPOSE:To permit the stable work by preventing the intrusion of moisture of a brake body by allowing the electric current which forms the max. brake power except during wire feed, to flow into a power brake, and obtaining the uniform state of powder, thus preventing the variation of brake power of the electrode. CONSTITUTION:According to the control program of a memory 20, an electric- current control circuit 17 is operated also except in the case when a wire feeding signal is ON, and the electric current value supplied into a powder brake 3 is controlled to the value corresponding to the max. notch of a selecting switch 18. When the wire feeding signal is ON, control is performed so that the electric current set by the switch 18 flows in the brake 3. Therefore, the tension of a wire electrode can be controlled to a prescribed value, and the powder in the brake 3 is always made uniform except in the case when an electrode is supplied, and the intrusion of moisture can be prevented, and the variation of the brake power of the brake 3 can be easily suppressed on the start of feeding of the electrode.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wire electrical discharge machining device, particularly to preventing fluctuations in the braking force of a powder brake that controls the tension of a wire electrode. [Prior Art] Second The figure is a configuration diagram showing the wiring route of the wire electrode of a wire electrical discharge machining device. In the figure, (1) is the wire electrode, (
2) is a wire supply bobbin that supplies the wire electrode (1);
(3) is a powder brake that controls the tension of the wire electrode (1) sent from the wire supply bobbin (2), (4) is the wire feed motor, and (5) is the object placed on the XY dicross table (not shown). Workpiece, (6) is a damper roller, (7), (8), α0, (ISl is a pulley, (9) is a wire holder, (1υ, α fathom is a power supply die,
(121, H is a die guide, αe is a pinch roller.

A conventional wire electrical discharge machining device is configured as described above, and the wire electrode (1) is passed through the wire supply bobbin (2), each pulley, and then transferred to the powder brake (3) and wire feed motor (4) to be machined. Create a predetermined wire tension at the orthogonal part of the object (5) and the wire electrode (1).
1) and the workpiece (5), a voltage is applied between the wire electrode (1) and the workpiece (5), and electrical discharge is generated between the two to perform electrical discharge cutting. Let's do it.

The above powder brake (3) and wire feed motor (4)
) A block diagram of a control circuit for controlling the tension of a predetermined wire electrode (1) is shown in FIG. (17) is a current control circuit that controls the current flowing to the excitation coil built in the powder brake (3), and α is a current control circuit that controls the current value to vary the strength of the braking force of the powder brake (3).For example, 1 It is a 12-notch changeover switch.

Generation of a predetermined tension on the wire electrode (1) is performed using the changeover switch α.
After manually adjusting υ to the specified notch, turn on the wire feed υ.
By inputting a signal to the NC control device (not shown), the stain flow control circuit αD is operated, and the powder brake (3) is activated.
In electrical discharge cutting, the machining speed and precision of the cut surface can be improved by increasing the tension of the wire electrode. ) are likely to break, and the discharge becomes unstable. Therefore, selection of the tension of the wire electrode (1) is important and directly affects processing performance.

[Problem that the invention seeks to solve]

In the conventional wire electrical discharge machining device as described above, the powder brake (3) that controls the tension of the wire electrode (1) is an electromagnetic brake, and when no current is applied to the excitation coil, the internal powder is If the condition is unbalanced or moisture is easily absorbed, the torque characteristics may vary greatly when the current is applied, resulting in a stable cine. For this reason, the wire electrode (1
), the machining speed and machining accuracy of electrical discharge cutting machining fluctuated, resulting in unstable machining.

This invention was made to solve these problems, and it prevents moisture in the powder brake body even when the wire is not being fed, and also reduces variations in the tension of the wire electrode by making the internal powder uniform. An object of the present invention is to obtain a wire electrical discharge machining device capable of performing electrical discharge cutting.

[Means for solving problems]

In the wire electrical discharge machining apparatus of the present invention, a current is applied to the powder brake that controls the tension of the wire electrode so that the braking force becomes maximum at times other than when the wire is being fed.

[Effect]

In this invention, it is possible to prevent moisture in the powder brake body even when the wire is not being fed, and the state of the internal powder can be made uniform, so that the braking force of the wire electrode when starting wire feeding can be reduced. Fluctuations can be prevented [Embodiment] FIG. 1 is a block diagram of a powder brake control circuit according to an embodiment of the present invention, (3) in the figure.

tin and Qa indicate the same parts as the above conventional device. (
A) The memory in the NC control device stores the control program input from the paper tape and outputs it to the current control circuit αD.

The control program stored in memory 4 works to operate the current control circuit αη even when the wire feed signal is not at 08:00, and the current value flowing to the powder brake (3) at that time is set by the changeover switch (Japanese style at the maximum notch of 18). The current is controlled to a roaring current value (in other words, the maximum current) and is automatically controlled so that it flows to the muddy brake (3).

Further, when the wire feed signal is 08:00, control is performed so that the current set by the changeover switch aυ flows to the powder brake (3) as in the conventional case.

In the wire electrical discharge machining apparatus configured as described above, a powder brake (3
), apply a current that maximizes the braking force to the wire electrode (
During feeding in step 3), the tension of the wire electrode (3) is controlled to a predetermined value by flowing a current that produces a predetermined braking force. Therefore, the condition of the powder in the powder brake (3) changes when the wire electrode (1) is not being fed. The wire electrode (3
) It is possible to easily suppress fluctuations in the braking force of the powder brake (3) even at the start of the powder brake (3).

The wire electrode (1) is wired as shown in Figure 2 when the wire electrode is stopped feeding, and at this time the maximum current flows through the powder brake (3) and the braking force is at its maximum. It is also possible that wiring is difficult because of this. Therefore, by inputting the next input signal for wiring the wire electrode (1) to the NC control device, the time for wiring the wire electrode (1), for example, about 10 minutes, is changed to the current control circuit (17). If a control program is stored in the memory in the NC control device so that the minimum current flows to the powder brake (3), the wire electrode (
1) It becomes possible to control the braking force of the powder brake (3) during wiring.

〔Effect of the invention〕

As explained above, this invention reduces fluctuations in the tension of the shear wire electrode by preventing fluctuations in the braking force of the powder brake, thereby stabilizing the machining speed and machining accuracy of cutting with a wire electrical discharge machining device. effective.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a powder brake control circuit according to an embodiment of the present invention, Fig. 2 is a configuration diagram showing a wire electrode wiring route of a wire electric discharge machining device, and Fig. 6 is a block diagram of a conventional powder brake control circuit. It is. (1)...Wire electrode, (2)...Wire supply bobbin, (3)...Powder brake, (4)...Wire feed motor, (5)...Workpiece, (6 )...damper roller, (7), (8), αQ. a9...Pulley, (9)...Wire holder, αυ,
αku...power supply die, (13, (13...dice guide, αe...pinch roller-1 housing η...current control circuit, cod...changeover switch, wire...memory. , The same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A workpiece is placed on an XY cross table that moves forward and backward in the X-axis direction and the Y-axis direction, and a wire electrode that moves in the Z-axis direction with a predetermined tension is orthogonally crossed to this workpiece. In wire electrical discharge machining equipment, which cuts the workpiece into a desired shape by applying a voltage between the workpieces and moving the workpiece while generating an electric discharge, wire feeding is used to control the tension of the wire electrode. A wire electrical discharge machining device characterized in that a current that maximizes braking force is passed through a portion other than the inside.